perf(ui): retain shaped report text

src/AcDream.App/UI/Layout/CharacterController.cs

@@ -67,12 +67,13 @@ public static class CharacterController
     internal static IReadOnlyList<string> AugmentationStringKeys
         => Augmentations.Select(descriptor => descriptor.StringKey).ToArray();
 
-    public static void Bind(
+    public static CharacterInformationUiController Bind(
         ImportedLayout layout,
         Func<CharacterSheet> data,
         UiDatFont? datFont = null,
         Action? close = null,
-        CharacterInfoStrings? strings = null)
+        CharacterInfoStrings? strings = null,
+        Func<Action, IDisposable>? subscribeChanged = null)
     {
         ArgumentNullException.ThrowIfNull(layout);
         ArgumentNullException.ThrowIfNull(data);
@@ -96,11 +97,19 @@ public static class CharacterController
 
         CharacterInfoStrings copy = strings ?? CharacterInfoStrings.English;
         text.PreserveEndOnLayout = false;
-        text.LinesProvider = () => IndicatorDetailText.Shape(text, BuildReport(data(), copy));
-        if (layout.FindElement(ScrollbarId) is UiScrollbar scrollbar)
+        UiScrollbar? scrollbar = layout.FindElement(ScrollbarId) as UiScrollbar;
+        if (scrollbar is not null)
             scrollbar.Model = text.Scroll;
-        if (layout.FindElement(CloseId) is UiButton closeButton)
+        UiButton? closeButton = layout.FindElement(CloseId) as UiButton;
+        if (closeButton is not null)
             closeButton.OnClick = close;
+        return new CharacterInformationUiController(
+            text,
+            data,
+            copy,
+            subscribeChanged,
+            scrollbar,
+            closeButton);
     }
 
     internal static string BuildReport(CharacterSheet sheet, CharacterInfoStrings strings)
@@ -330,6 +339,69 @@ public static class CharacterController
         bool IncludeValue);
 }
 
+/// <summary>
+/// Event-invalidated report owner for retail's character-information text.
+/// Stable frames borrow the same shaped line collection.
+/// </summary>
+public sealed class CharacterInformationUiController : IRetainedPanelController
+{
+    private readonly Func<CharacterSheet> _data;
+    private readonly CharacterInfoStrings _strings;
+    private readonly UiTextLayoutCache<string> _layout;
+    private readonly IDisposable? _changeBinding;
+    private readonly UiScrollbar? _scrollbar;
+    private readonly UiButton? _close;
+    private bool _contentDirty = true;
+    private bool _disposed;
+
+    internal CharacterInformationUiController(
+        UiText text,
+        Func<CharacterSheet> data,
+        CharacterInfoStrings strings,
+        Func<Action, IDisposable>? subscribeChanged,
+        UiScrollbar? scrollbar,
+        UiButton? close)
+    {
+        _data = data;
+        _strings = strings;
+        _scrollbar = scrollbar;
+        _close = close;
+        _layout = new UiTextLayoutCache<string>(
+            text,
+            static (target, value) => IndicatorDetailText.Shape(target, value),
+            string.Empty,
+            StringComparer.Ordinal);
+        text.LinesProvider = GetLines;
+        _changeBinding = subscribeChanged?.Invoke(InvalidateContent);
+    }
+
+    private IReadOnlyList<UiText.Line> GetLines()
+    {
+        if (_contentDirty)
+        {
+            _layout.SetValue(CharacterController.BuildReport(_data(), _strings));
+            _contentDirty = false;
+        }
+        return _layout.GetLines();
+    }
+
+    private void InvalidateContent() => _contentDirty = true;
+
+    public void OnShown() => InvalidateContent();
+
+    public void Dispose()
+    {
+        if (_disposed)
+            return;
+        _disposed = true;
+        _changeBinding?.Dispose();
+        if (_scrollbar is not null)
+            _scrollbar.Model = null;
+        if (_close is not null)
+            _close.OnClick = null;
+    }
+}
+
 public sealed record CharacterInfoStrings(
     string[] Birth,
     string[] Played,